Four unidentified men seen outside the residence of Alok Verma, the CBI director who was send on leave, have been held by his private security officers on Thursday.

The identity of the suspects and their motives were yet to be ascertained, but they were reportedly caught snooping outside Verma's CBI House residence on Janpath. Meanwhile, NDTV reportedthat the detained men were actually Intelligence Bureau officials keeping a watch on Verma.

The suspects were intercepted when Verma's chief security officer found them sitting in a car parked a little away from his residence, said sources.

The Delhi Police and the Central Bureau of Investigation (CBI) teams are looking into the matter.

The development comes amid Verma's charge that the Centre was undermining his authority and interfering in the CBI's investigations. In his petition, Verma emphasised the need to allow the CBI "to function completely independently and autonomously", but said: "There are bound to be occasions when certain investigations into high functionaries do not take the direction that may be desirable to the government."

This is a significant remark, given the allegations that Verma was removed from his post for "asking too many questions" about the Rafale fighter jet deal.

Amid the infighting between Verma and his deputy Special Director Rakesh Asthana, CBI special director and his second in command were sent on forced leave. The government instead appointed M Nageshwar Rao as the interim chief of the CBI on Wednesday. The decision was made at a time when Verma was at loggerheads with Asthana, who was booked by the investigating agency in an alleged bribery case. Both Verma and Asthana, who is believed to be the "prime minister's favourite", were divested of their roles and responsibilities at the CBI late on Tuesday.